JPS632700Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a mechanical seal, and an object of the present invention is to provide a mechanical seal structure that prevents seizure of sliding parts.

Conventionally, as shown in FIG. 1, when sealing the shaft between the housing 1 and the rotating shaft 2, there is a fixed sliding ring 3 that is airtightly supported on the housing 1 side and a rotating ring that is airtightly supported on the rotating shaft 2 side. There is a mechanical seal that has a structure in which the sliding ring 4 slides and rotates in close contact with each other due to elastic force, but this type of mechanical seal has a flat sliding surface, so it is difficult to generate heat due to sliding. Therefore, as shown in Figure 2, the sliding surface F has an inner height of F ₁ and an outer height of
F ₂ distortion occurs, which not only impairs sealing performance, but also causes seizing or abnormal leakage due to unexpected circumferential transient folding distortion, which reduces the reliability of mechanical seals. Ta.

In view of the above-mentioned drawbacks, the present invention has been developed by undulating the sliding surface of a mechanical seal in the circumferential direction at predetermined intervals when high heat is generated, and forming an oil film in the minute gaps to maintain the sealing effect and improve the sliding surface. The present invention aims to improve the sealing performance of mechanical seals by providing a sliding material that lowers the coefficient of friction of surfaces, prevents seizure, and reduces sliding torque.

In other words, the mechanical seal of the present invention is formed by coating, plating, overlay welding, or other techniques such as coating, plating, or overlay welding the material of the end surface on the end surface of the metal base on the sliding end surface of either the fixed sliding ring or the rotating sliding ring. When hardening, several grooves to more than 10 grooves are arranged evenly in the circumferential direction on the metal end surface of the base metal, and the sliding surface including the grooves is hardened to a flat surface. The above-mentioned folding strain is formed on the hardened surface.

The embodiments of the present invention will now be described with reference to the drawings. FIGS. 3, 4 and 5 are plan views of a sliding ring 5 consisting of a fixed sliding ring 3 or a rotating sliding ring 4. , FIG. 6 is a cross-sectional view taken along line A--A.
The sliding material 5 has a hard coating layer 7 formed by plating, overlay welding, etc. on one end side of the metal base 6 to form a flat sliding surface F, and the metal base on the side on which the hard coating layer 7 is applied. Several to ten or so grooves 8, 8, . . . are formed in advance on the metal 6 surface evenly in the circumferential direction. Each of the grooves 8 may have parallel grooves arranged radially as shown in FIG. A conceivable option is one in which inverted tapered grooves are arranged radially, as shown in FIG.
The cross-sectional shape of can be configured in various shapes such as a square shape (see FIG. 7), a round shape (see FIG. 8), and a dovetail shape (see FIG. 9). When the hardened coating layer 7 is applied to the surface of the metal base ₆ having the grooves 8, 8..., as shown in FIG. The hardened coating layer 7 is thicker than the thickness t ₁ of the hardened coating layer 7 and has two regular repeating thicknesses in the circumferential direction.

In the figure, 10 is a mechanical seal cover fixed to the end of the housing 1, 11 and 12 are O-rings, and the rotating sliding ring 4 is elastic between it and the spring collar 13 externally fixed to the rotating shaft 2. It is always pressed against the fixed sliding ring 3 by a spring 14 installed therein.

The sliding member 5 having the above structure is arranged on the sliding surface of the fixed sliding ring 3 or rotating sliding ring 4 of the mechanical seal shown in FIG. 5 thermally expands, due to the difference in the thickness of the hardened coating layer 7 and the difference in mechanical properties such as the coefficient of thermal expansion between the hardened coating layer 7 and the metal base 6, the sliding surface F of the hardened coating layer 7 has a shape as shown in FIG. A folding distortion W consisting of regular waveform radial unevenness is generated. This folding strain W causes a slight gap to be formed between the sliding surface and other sliding surfaces, and the sealing liquid filled in the mechanical seal enters the gap to form an oil film layer, which improves the sealing effect. While maintaining the friction coefficient of the sliding surface, the friction coefficient of the sliding surface is lowered, and heat generation and burnout of the part are suppressed.

As explained above, according to the present invention, the ratio of the thickness of the metal base of the fixed sliding ring or the rotating sliding ring to the coating layer changes regularly in the circumferential direction. Since the metal base metal and the coating layer have different coefficients of thermal expansion, the sliding heat generates folding strain that changes regularly in the circumferential direction on the sliding surface, creating gaps that extend in the radial direction. becomes. Therefore, according to the invention of the present invention, not only is there no chance of leakage occurring due to undesirable distortion on the sliding surfaces, but also an oil film layer is formed between the sliding surfaces, which improves lubricity. can provide excellent mechanical seals.

[Brief explanation of drawings]

The drawings show an embodiment of the mechanical seal of the present invention, in which Fig. 1 is a half-cut sectional view of the main part of the mechanical seal, and Fig. 2 is a front sectional view showing a conventional sliding member.
Figures 3 to 5 are plan views of sliding members of the present invention with different groove shapes, Figure 6 is a sectional view taken along line A-A, Figures 7 to 9 are end views of the grooves, and Figure 10. is a developed cross-sectional view in the circumferential direction showing the surface condition of the sliding material when it generates heat. DESCRIPTION OF SYMBOLS 1... Housing, 2... Rotating shaft, 3... Fixed sliding ring, 4... Rotating sliding ring, 5... Sliding material, 6...
...Metal base, 7...Hardened coating layer, 8...
Concave groove.

Claims (1)

[Scope of utility model registration request] In a mechanical seal that performs a sealing action by the sliding movement of a fixed sliding ring and a rotating sliding ring, the fixed sliding ring or the rotating sliding ring has several to more than 10 diameter holes on the end face on the sliding surface side. It consists of a metal base with grooves arranged evenly in the circumferential direction, and a coating layer formed on the end surface, and the sliding surface of the coating layer has regular grooves in the circumferential direction due to heat generated by sliding. A mechanical seal characterized by the occurrence of folding distortion that changes.